The present invention relates to a retinal scanning image display apparatus that draws an image on a retina of an observer by guiding a light flux modulated in accordance with a video (image) signal to a pupil of the observer and scanning the light flux two-dimensionally.
In an image display apparatus as stated above, an image is drawn directly on the retina through the pupil of the observer by scanning laser light two-dimensionally. Among this sort of apparatuses, there is an apparatus adapted to detect the motion of the pupil of the observer and causes laser light to enter the pupil so as to follow the motion, thus avoiding the image from disappearing even when the observer moves their pupils (see Japanese Patent Laid-Open No. 7 (1995)-135623).
As shown in FIG. 6A, however, when the pupil Ea of the observer shifts (rotates) from position P10 to position P11, the converging point P10 of the image light flux La1, Lb1, and Lc1 needs to be shifted to P11 so as to keep it within the pupil Ea.
In FIG. 6A and FIGS. 6B, 6C and 7 described later, La1, La2, and La3 represent center light fluxes of an image, and Lb1, Lb2, and Lb3 and Lc1, Lc2, and Lc3 represent light fluxes at the edges of the image.
As shown in FIG. 6B, when the image light fluxes La1, Lb1, and Lc1 are shifted to be La2, Lb2, and Lc2, the incident angles of the image light fluxes to the pupil Ea will be different from than those in FIG. 6A. Therefore, the image appears displaced to the observer. To prevent this, the image light fluxes La1, Lb1, and Lc1 need to be shifted in parallel to be La3, Lb3, and Lc3, as shown in FIG. 6C.
As shown in FIG. 7, Japanese Patent Laid-Open No. 10 (1998)-319342 discloses an image display apparatus that converges light fluxes from a display panel 121 by means of a microlens array 122 and an ocular lens 123 to guide them to the pupil Ea of the observer.
This image display apparatus changes the converging position of the image light fluxes so as to follow the movement of the pupil Ea and controls the incident angles thereof to the pupil Ea to be kept constant even when the converging position is changed. In other words, the displacement of the image becomes less recognizable even when the pupil Ea moves.
More specifically, when the pupil of the observer shifts from P12 to P13, then the microlens array 122 is driven in the direction of the arrow F, so as to shift the converging position of the image light fluxes La1, Lb1, and Lc1 (La2, Lb2, and Lc2) to position P13. At the same time, the display position of the display panel 121 is shifted, so that the image light fluxes La2, Lb2, Lc2 for the pupil Ea located at P13 indicated by solid lines are in parallel with the image light fluxes La1, Lb1, and Lc1 for the pupil Ea located at P12.
Japanese Patent Laid-Open No. 2004-191962 discloses a retinal scanning image display apparatus that detects the eye direction of the observer and changes the incident angles of the image light fluxes to the pupil in accordance with the detection result.
In the apparatus disclosed in Japanese Patent Laid-Open No. 10 (1998)-319342, however, there is a need to secure an extra display area of the display panel beforehand in order to keep the incident angles of the image light fluxes to the pupil Ea constant. Therefore, there is a problem of increasing the display panel in size.
In the apparatus disclosed in Japanese Patent Laid-Open No. 2004-191962, a change of the eye direction causes a change of the image position.